MEDICAL DEVICE: The medical device used in this clinical study is the OncoSorb® column. It is used with a specially modified Fresenius ART apheresis machine, associated tubing sets and an Albuflow plasma filter, also from Fresenius. These components comprise the extracorporeal immune apheresis system. The OncoSorb® column was CE certified in April 2008. The OncoSorb® device is intended to specifically adsorb three soluble receptors (sTNF-R1, sTNF-R2 and sIL-2R α), which are known to inhibit the natural immune response of cancer patients mediated via tumor necrosis factor α (TNF- α).